<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="text"id="ipt">
    <div></div>
</body>
<script>
       var ipt= document.querySelector('#ipt');
    var divs = document.querySelector('div')
    var debounce = function(fn,interval){
        var _self=fn,
            timer = null
            return function(){
                // this指向input
                var _me = this

                console.log(this)
                args = arguments;
                if(timer){
                    clearTimeout(timer)
                }
                timer = setTimeout(function(){
                    _self.apply(_me,args)

                },interval || 500)
            }
    }
    ipt.addEventListener('input',debounce(function(e){
        console.log(e.target.value)
        divs.innerHTML = e.target.value
    },500))
    ipt.addEventListener('focus',function(){
        divs.classList.add('show')
    })
    inp.addEventListener('blur',function(){
        divs.classList.remove('show')
    })
    
    Function.prototype.myCall = function(){
        console.log("myCall")
    };

    console.dir(Function);
    Array.prototype.slice.myCall();
</script>
</html>